Electron tube clamp



Sept. 15, 1959 F. J. SKWAREK ELECTRON TUBE CLAMP Filed Nov. 1, 1957 .K M mm 4 N 4 2 mm M WE ms WW J 5 K v,

4U Q MW? ma "BR ZTORNEYS United States Patent ELECTRON TUBE CLAMP Frank J. Skwarek, Westbury, N.Y., assignor to Polarad Electronics Corporation, Long Island City, N.Y., a corporation of New Yorlr Application November '1, 1957, Serial No. 693,917

7 Claims. (Cl. 324-20) This invention relates to improvements in electronic tube testing devices and in particular to an improved clamp used to secure electron tubes during a test operanon.

Certain types of electron tubes, of which the externalcavity klystron tube and the lighthouse tube are examples, have, in addition to conventional baseplug and anode terminals, one or more special terminals (usually for grid electrodes) in the form of an annular metal contact ring extending outwardly of its envelope. Such tubes may be termed ring-terminal tubes. During testing operations these rings are required to be electrically grounded, or connected in some other Way to the instrument circuitry.

Ring-terminal tubes vary in size and shape so that different types have differently sized and spaced ring terminals. Consequently it has been difiicult to provide a single instrument capable of fitting all the known sizes and types of such tubes. Impracticable attempts have been made to overcome this ditficulty, as by providing a number of slip rings of representative sizes that can he slipped into contact over the ring terminals of the tube. This method is obviously unfeasible as it encumbers the test instrument with often unnecessary rings, leads, etc.

It is an object of this invention to provide an instrument combining a clamp with contact means for the annular ring terminals of such tubes.

Another object is to provide a device to greatly simplify the operations of ring-terminal tube testing devices.

A further object is to provide a device capable of universal use with ring-terminal tubes of different sizes and structures.

Yet another object is to provide a device that is capable of swift, easy manipulation and that is inexpensive and simple to fabricate.

Other and more detailed objects and advantages of this invention will become obvious from the following description and the appended drawings in which Fig. 1 is an isometric view of a device embodying this invention;

Fig. 2 is a vertical cross-section view along line 2-2 of Fig. 1 showing the tube inserted and held within the device;

Fig. 3 is a similar vertical cross-section view of Fig. 1 along line 22 without the tube;

Fig. 4 is an end view of Fig. 1 viewed along line 44, and

Fig. 5 is a cross-section view of Fig. I viewed along line 55.

When a pair of flat leaf metal strips such as leaf springs are fastened together at their outer ends they may be used to clamp objects between them by simultaneously pulling the ends away from one another. The present invention utilizes one or more such pairs of strips by mounting each pair on a pair of pivoting arm units and providing means for varying the distance between the end of the strips and for continually urging the ends apart.

An electron tube may thus be clamped and at the same time contact may be made with its annular grid rings.

In the drawing, the specific embodiment shown comprises a pair of cylindrical shafts 10 and 11 mounted on vertical posts 12 integrally formed at each of the corners of a substantially rectangular base 13. On each of the shafts 10 and 11 a pair of L-shaped arm units or bellcranks 14 is pivotally mounted, each arm unit 14 having a horizontal arm 15, a vertical arm 16, a flange 17 extending from the end of the vertical arms 16, and a notch 18 cut in the upper corner of the outer end of horizontal arm 15.

These arm units 14 are pivotally mounted on the shafts 10 and 11 through cylindrical hubs 19 secured adjacent the bend at the junction of the horizontal arm 15 and vertical arm 16 of each of the arm units 14.. These units are so mounted that the ones on shaft 10 are in opposed paired relationship to corresponding units on the other shaft 11, and the ends of the horizontal arms 15 meet substantially tangentially. The flanges 17 of the two units 14 mounted on the same shaft 10 or 11 extend inwardly toward each other.

Two leaf metal springs 20 and 21 are positioned against one another and have one set of juxtaposed ends clamped to a flange 17 of an arm unit 14 on shaft 10 and their other set of juxtaposed ends are clamped to the corresponding flange of the opposite arm unit 14 on shaft 11. A similar pair of flat strips 30, 31 is similarly mounted between the remaining pair of flanges 17. A coil tension spring 22 is stretched and attached between the vertices of each pair of corresponding arm units 14. Each coil spring 22 tends to pivot its coupled arm units 14 so as to cause their vertical arms 16 to pull on the ends of the leaf spring pair 20 and 21 or 30 and 31, as the case may be.

One pair of corresponding arm units 14, coupled to leaf spring pair 20, 21 is retained adjacent its posts 12 by clips 23 so as to prevent them from moving laterally along the shafts 10 and 11. The other corresponding arm units 14 coupled to leaf spring pair 30, 31 are jointly movable in a lateral direction. Each of these arm units 14 is pivotally secured at hub 19 on a movable sleeve 32 mounted about shafts 10, 11, and are connected for joint movement by a yoke 24 secured to sleeves 32. Clip 33 and sleeve shoulder extension 34 retain the arm units 14 in fixed position on the sleeve 32. A handle 25 is provided on yoke 24 to facilitate the movement of these arms.

A lever arm 26 is pivotally mounted by a hub 35 at one end to shaft 10. The lever 26 has a crossbar 27 positioned along its length so that the bar rests at each end within the adjacent end notches 18 in the two pairs of horizontal arms 15 of the units 14.

It can be seen from Fig. 2 that when the lever 26 is depressed the arm units 14 are pivoted so that the distance between the ends of the flat springs 20, 21 and 30, 31 is decreased and each flat spring pair is forced to separate and open. With the release of the lever arm 26 the coil spring 22 forces a reverse pivoting of the arm units 14 tending to pull the springs of each pair together.

It may readily be seen that in certain types of ringterminal tubes with two rings, the axial distance between the annual rings may be different than in other types. Thus by laterally varying the distance between the pairs of corresponding arm units 14 and springs 20, 21 and 30, 31, various types of tubes may be accommodated. It will also be noted that when the lever 26 is released each pair of corresponding arm units 14 responds to its respective coil spring 22 independently of the other and the device is therefore capable of simultaneously clamping contact rings of different diameters.

The leaf metal springs 20, 21 and 30, 31 are provided 2,904,747 I V i with a plurality of bentfingers 36 on the inner edges to permit the clamping of'certain tubes in which the ringterminals are formed of narrow annular flanges or grid extensions. The bent fingers '36 provide the leaf spring with a grooved surface and increase the possible number of points of contacts so as to facilitate the secure clamping of such tubes.

The contact rings of the tube under test are electrically grounded in this embodiment by making each of the parts of the device conductive and by connecting the base to the chassis of the complete testing instrument, which is normally grounded. Howeven-diiferent potentials may be applied to the tube ring-terminals 'by insulatedly mounting the pairs of leaf springs 20, 21 or '30, '31 on their respective flanges 17 in obvious manner.

It is obvious that numerous modifications may be made of this device; for example it may be adapted to clamp tubes having either a single annular ring-terminal or tubes having a number of ring-terminals by varying the number o'f-corresponding arm units and coupled leaf springs, the bellcrank arm units may be replaced by other equivalent lever means. It is therefore :desired not to be limited by the disclosure :as set forth herein, which -is illustrative only, but only by the claims as appended hereto.

What is claimed as the invention is:

1. A testing clamp for electron tubes or the like comprising, in combination, a base having vertical *posts integral therewith, a pair of cylindrical shafts spaced therefrom and mounted on said posts, 'two L-shaped members pivotally mounted on eachof said cylindrical shafts, each of said -L-shaped members having 'a vertical arm, and a horizontal arm and means adjacent the junction of said arms for mounting said member on said shaft, said L-shaped members mounted on one shaft being in opposed corresponding relationship to said L-s'haped members mounted on said other shaft, a pair of clamp members each-comprising a pair of flat metal leaf springs fastened together at both ends, each of said clamp members being fastened at'eac'h of itsends to a corresponding vertical arm of an opposed pair of said L'shaped members, a pair of helical springs each attached at one end to the vertex of a respective one of said L-shaped members and at the otherend-to the vertex 'of its corresponding L-shaped member and urging said corresponding vertical arms apart, a lever arm pivotally mounted adjacent one end on one of said shafts between said L-shaped members and having a cross piece perpendicularly disposed to its longitudinal axis and positioned along its length and resting upon each of said horizontal arms, whereby by depressing said lever arm said L.-shaped members may be caused to pivot opening said leaf spring clamp members for the insertion of an electron tube or the like therein.

2. A :clamp as :claimed in claim 1 wherein means are provided for "causing one pair of said correspondingly mounted L-shaped members to .move simultaneously in a lateral direction along their respective shafts.

3. A clamp as claimed in claim 2 wherein said means for causing lateral movement of said EL-s'haped members comprises a yoke connecting said one corresponding pair of L-shaped members.

4. A clamp as claimed in claim 1 wherein said clamp members are electrically grounded to said base.

5. A clamp for electron tubes and the like comprising in combination a'base, a pair of arm members pivotally mounted thereon, a pair of flat metal leaf spring clamp members fastened at each end respectively to said arm members, spring means for continually urging said arm members apart to cause said clamp members to approach one another, and means for pivoting said arm members inwardly of each other to separate said clamp members whereby said "clamp members may be caused to receive and hold an electron tube or the like.

6. A clamp as claimed in claim 5 comprising at least one further pair of arm members, each said further pair of arm members having a pair of said metal leaf spring clamp members fastened thereto, and means for varying the 'lateral distance between each pair of said arm members.

7. A clamp 'as claimed in claim 5 wherein said clamp members are electrically grounded to said base.

References Cited in the tile of this patent UNITED STATES PATENTS 1,832,677 'Wildeboer Nov. 17, 1931 2,298,822 Conrad Oct. 13, 1942 2,379,060 Bacheldor June 26, 1945 2,397,985 Schriefer Apr. 9, 1946 

